1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to restoring state information of a remote user interface (RUI), and more particularly, to restoring an RUI in a Universal Plug and Play (UPnP) environment.
2. Description of the Related Art
FIG. 1 is a block diagram of a conventional Universal Plug and Play (UPnP)-based remote user interface (RUI) network system (“the system”). Referring to FIG. 1, the system includes an RUI control point (CP) 11, an RUI client 12, and an RUI server 13. Here, the RUI Control Point (CP) 11 corresponds to a UPnP CP supporting a remote user interface, and the RUI client 12 and the RUI server 13 correspond to a UPnP controlled device (CD) supporting the remote user interface.
According to UPnP, the RUI CP 11 discovers and controls the RUI client 12 and the RUI server 13. The RUI client 12 and the RUI server 13 that are connected under the control of the RUI CP 11, process a request and response received via an RUI according to out-of-band remote protocol, such as remote desktop protocol (RDP) and extended remote technology (XRT) protocol.
FIG. 2 is a diagram illustrating a conventional process of storing and restoring state information of an RUI according to UPnP. In particular, the process of FIG. 2 is related to a case where a connection of a first RUI client 22 to an RUI server 24 is changed to a connection of a second RUI client 23 to the RUI server 24.
In operation 201, the RUI CP 21 searches for RUI connections that are currently in progress by calling GetCurrentConnection( ) to the first RUI client 22, and learns a connection to the RUI server 24 from the searched RUI connections.
In operation 202, the RUI CP 21 calls SetUILifetime( ) to the RUI server 24 in order to instruct the RUI server 24 to maintain the RUI connections that are currently in progress, for a predetermined time.
In operation 203, the RUI CP 21 calls Disconnect( ) to the first RUI client 22 in order to terminate the RUI connections that are in progress.
In operation 204, the RUI CP 21 calls Connect( ) to the second RUI client 23 in order to start the RUI connections maintained according to the instructions given in operation 202.
However, as described above, the conventional method of FIG. 2 is applicable only to a remote protocol model which allows all state information of URIs to be stored in an RUI server. However, in the case of a HyperText Transfer Protocol (HTTP)-based remote protocol model, when a transaction that processes a request and a response is completed, the state information of a remote interface is lost and is not stored due to the stateless characteristics of the HTTP, and therefore, the RUI client manages most of the state information.
Accordingly, the conventional process of storing and restoring state information of an RUI according to UPnP is applicable to remote protocol models, such as RDP and XRT, in which all state information of RUIs is stored in an RUI server. However, the conventional process has a problem in that it cannot be applied to remote protocol models, such as HTTP, in which most of the state information is managed by an RUI client. In particular, binary protocol-based RDP and XRT need a wider network bandwidth than HTTP. Therefore, since a HTTP-based RUI is widely used, the above problems exist.